Cloudflare offers a dedicated SSL cert for $5 a month vs. their free shared certs. That may seem expensive, but if you go with Let's encrypt, their free certs expire in 3 months. After renewing your cert a few times, you may gladly want to pay the $5.
Cpanel has modules for Let's encrypt and Comodo, which offer free certs and auto renews every two months so that is a good solution for blogging websites. Certbot can be installed on dedicated servers and does the same thing.
For E-commerce websites, I would suggest you pony-up the money to get a real cert, but for a blogging website, I think Cloudflare's "full SSL" open would be sufficient. You would simply need a self-signed cert on your server and you would be all set. The "Flexible SSL" option is for lazy or incompetent people IMHO.